How do you recognise damage to an O-ring and how do you fix it?
Editorial team|3 minutes to read
O-ring seals are used in all areas of industrial technology: damage to O-rings increases the risk of machines leaking or malfunctioning. The wrong size, type or application can lead to problems. With the tips below, we will help you prevent damage to O-rings. Read on!
Causes of leakage
O-ring leakage often has one of these three reasons:
- Wrong size
Determine the size using a measuring cone or this formula: inner diameter x cord thickness (d1 x d2).
- Excessive stretching or compression
When internal and external diameters of O-rings change, this is often the result of excessive stretching and compression of the seal. The result: the O-ring does not fit properly. Prevent these problems by not allowing the internal diameter to stretch by more than 5% and the external diameter to shrink by less than 3%.
- Material does not fit the application
An O-ring does not function properly or is damaged when the wrong material is chosen for the relevant application.
Most common types of damage
- Compression set
After compression of an O-ring, a permanent deformation takes place. In most cases the material returns to its original shape, in some cases permanent deformation takes place: this is called compression set. When the O-ring does not return to its original shape, this can cause leaks.
Recommendation: Choose a material with a high temperature resistance. In addition, a compression set is affected by the use of incorrect groove dimensions. Therefore, it is advisable to check the groove dimensions for the application.
- Influence of ozone
When an O-ring comes into prolonged contact with direct sunlight, this accelerates its ageing process. Think for example of the development of hair cracks.
Recommendation: Ensure better heat, weather and ozone resistance. Check our range of O-rings here.
- Twisting
During an application, an O-ring can rotate, which can lead to damage.
The cause: The causes of a rotating O-ring are too high compression, an incorrect groove or a lack of lubrication.
Recommendation: Use an x-ring. These are rings that require less friction due to less compression. In addition, x-rings are stabilising and seal better in dynamic applications. Check our range of X-rings. Still want to use an O-ring? Then choose the correct lubricant.
- Installation damage
When using the wrong tools during fitting of O-rings, you increase the risk of damage.
Recommendation: Use an O-ring assembly kit when fitting or removing the rings. Twist and stretch the O-ring minimally during assembly. Check our range of assembly materials here.
- Overheating
An O-ring often has to withstand high temperatures. When an O-ring is used, but the temperature of the application exceeds the maximum temperature, this causes hardening . What is the consequence? The O-ring tears.
Advice: Choose a seal that is suitable for fluctuating and high temperatures. Get advice from our experts.
Our advice page
To help you choose the right product, our Kramp specialists have set up an advice page.
Do you have any questions?
Please contact a Kramp product specialist or contact us at knowledgecenter@kramp.com. Would you like to see all of the O-rings that we sell? Take a look in our web shop.
